example with musictheory.jl [skip ci]

Author: SteffenPL

examples/with_musictheory.jl

@@ -0,0 +1,55 @@
+using PortMidi, MusicTheory
+using MusicTheory.PitchNames
+
+Pm_Initialize()
+
+# 0. Get info about devices
+for i in 0:Pm_CountDevices()-1
+    info = unsafe_load(Pm_GetDeviceInfo(i))
+    if info.input == 0 
+        println(i, ": ", unsafe_string(info.name))
+    end
+end
+
+# 1. Select device
+id = 7  # change this number if needed
+print("Use: ", unsafe_string(unsafe_load(Pm_GetDeviceInfo(id)).name))
+
+# 2. Open device 
+stream = Ref{Ptr{PortMidi.PortMidiStream}}(C_NULL)
+Pm_OpenOutput(stream, id, C_NULL, 0, C_NULL, C_NULL, 0)
+# don't forget to call later: Pm_Close(stream[])
+
+# 3. Send MIDI messages to play notes
+Note_ON = 0x90
+Note_OFF = 0x80
+function play_note(stream, note, velocity, duration, delay = 0)
+    sleep(delay)
+    Pm_WriteShort(stream[], 0, Pm_Message(Note_ON, semitone(note), velocity))
+    sleep(duration)
+    Pm_WriteShort(stream[], 0, Pm_Message(Note_OFF, semitone(note), velocity))
+end
+
+# make a random tune using MusicTheory.jl
+scale = Scale(D[3], major_scale)
+notes = Iterators.take(scale, 14) |> collect
+begin
+    N = 100
+    offset = 0.99
+    beat = 0.45  # ms
+
+    @async for i in 1:N
+        nt = rand(notes)
+        rand() < 0.9 && @async play_note(stream, nt, rand(80:120), beat * (0.9 + 0.05*rand()))
+        sleep(beat * (1 + 0.001*rand()))
+    end
+
+    @async for i in 1:N
+        nt = rand(notes)
+        rand() < 0.9 && @async play_note(stream, nt, rand(80:120), beat * offset* (0.9 + 0.05*rand()))
+        sleep(beat * offset * (1 + 0.001*rand()))
+    end
+end
+
+# 4. Close device
+Pm_Close(stream[])